1. Technical Field
The invention relates generally to apparatus for fixing a seat cover to a seat frame, and more specifically to a reinforced seat welting. The invention also relates to seat weltings that are made of extruded plastic.
2. Related Prior Art
It is generally known to fix a seat cover to a seat frame with a seat welting. In such an arrangement, the seat cover surrounds a seat cushion supported by the frame and has a peripheral edge to which the seat welting is fastened. The seat welting can be fixed to the seat cover by sewing, stapling, with an adhesive, or by a combination of these methods. The seat welting is, in turn, fastened to the seat frame.
The seat welting can be fixed to the seat frame by a fastener or "hog ring" that surrounds a portion of the seat frame and that pierces the seat welting. It is also known to fix a welting to a seat frame by configuring the welting and a portion of the seat frame to be engageable with an interference fit. For example, it is known to provide a channel on the seat frame and to configure the seat welting so that the welting can be moved or snapped into the channel. An example of such an arrangement is shown in U.S. Pat. No. 3,273,178, which issued to Baruth et al. on Sep. 20, 1966.
It is also known to fix a welting to a seat frame by providing one or more projections on the frame and by providing a corresponding number of apertures in the welting. The welting is then pulled over the seat frame and fitted onto the projections. In such an arrangement, the engagement between the projections and the welting, and the tension in the seat cover, retains the welting on the seat frame.
In general, a seat welting provides a strip of material which is sufficiently flexible to be attached to the seat cover, and which has a sufficient strength to withstand the stresses placed on the welting during the assembly of the seat and during use of the seat. Accordingly, reinforced seat weltings are also generally known. For example, it is known to provide a reinforced seat welting by enclosing a flexible, incompressible material such as a rope or cord within a loop of fabric. An example of such a welting is illustrated in U.S. Pat. No. 4,558,904, which issued to Schultz on Dec. 17, 1985.
It is also generally known to provide a seat welting including an elongated member that is fixed to the seat cover and that is made of an extruded plastic material. Such extruded weltings are illustrated and described in the above referenced U.S. Pat. No. 3,273,178 and in U.S. Pat. No. 4,465,534, which issued to Zelkowitz on Aug. 14, 1984.
Because a seat welting is usually fixed first to a seat cover and then fixed to the frame, the welting should be somewhat pliant so as to be easily worked and positioned onto the frame. However, the welting should not be so flexible so as to be limp. Rather, the welting should have a "memory set" and be bendable into a position which it will retain until it is repositioned.
One of the problems associated with some known seat weltings is that the weltings include multiple parts requiring assembly before the weltings can be fixed to a seat cover or to a seat frame. Other difficulties encountered with known weltings include: a lack of sufficient strength to withstand the stresses placed on the welting; stiffness or inflexibility; and complete flexibility without a "memory set."